The present invention relates to vehicle seats and in particular to seats having elongated frame members made by extrusion, cut to length and assembled to slide rails to reduce the total number of components in the seat and to enable the use of the same components in seats of different widths.
Vehicle seats are typically constructed with a frame having three major components. At the base of the seat, the frame forms a pair of slide tracks with one slide track extending fore and aft along each lateral side of the seat. Each slide track includes a fixed rail mounted to a vehicle body and a slide rail movable fore and aft upon the fixed rail. A latch mechanism is provided to lock the slide rail in an adjusted position. The slide rail may include a riser which extends upwardly for attachment of additional frame components to the slide tracks. In any case, a cushion frame, generally rectangular in shape, is attached to the slide rails and supports a horizontal seat cushion.
The rectangular cushion frame typically carries a web, mat or spring suspension spanning laterally across the frame which in turn supports a foam pad. The suspension transfers the seating load to the side fore and aft extending members of the rectangular cushion frame. A portion of this seating load is then transferred to the front and rear lateral frame members of the cushion frame as a horizontal force component. The horizontal force applied to the front and rear lateral frame members of the cushion frame is contained within the rectangular cushion frame and is not transferred to the slide rails.
A back frame forms the third major component of the seat frame and is attached either to the slide rails or to the rear of the cushion frame. The back frame extends generally upwardly from the cushion frame and is generally rectangular in shape but may taper upwardly. A spring wire suspension extends vertically or horizontally across the frame to support a seat back foam pad. The back frame is often pivotally mounted for rotation about a transverse axis at the lower end of the back frame. A recliner mechanism is provided to lock the back frame in an adjusted position.
The cushion frame is typically formed of several stamped metal components which are welded together to form the rectangular frame. The frame generally includes front and rear laterally extending frame members and left and right fore and aft extending frame members. For each different size seat produced by a manufacturer, different length frame members are needed. A seat manufacturer must produce seats of many different widths. For example, a split bench seat results in two seats, each having a different width. Furthermore, the width of bucket seats will vary depending on the size of the vehicle in which they are installed. The stamped metal frame members are formed at their ends with structures which enable the members to be joined together. For each different width seat, different laterally extending frame members are needed. This results in significant tooling and storage costs for the numerous frame components which must be produced by a full line seat manufacturer.
It is an object of the present invention to reduce the number of frame components in a seat and to increase the number of common components in seats of different sizes.
It is a feature of the present invention to provide a seat structure in which the lateral frame components are manufactured as extrusions with a uniform cross section along their entire lengths. The lateral frame members are cut from long extruded stock to the desired length for the particular seat being assembled. Universal connecting blocks are used to couple the lateral frame members to the fore and aft frame members. Depending upon the width of seats ordered by a customer, the seat manufacturer merely cuts the frame members to the desired length and then assembles the seats. If there is a change in the mix of seat sizes being ordered, little time is required for the seat manufacturer to change tooling to cut different sized frame members and there is no overstock of frame members that are no longer needed. The seat manufacturer is thus better able to support just-in-time delivery of seats to a vehicle assembly plant.
In the case of a seat cushion frame, front and rear frame members are manufactured by cutting the frame members to length from an elongated extruded rail. The ends of the front and rear frame members are directly attached to the slide rails at opposite sides of the seat or connecting blocks are used which are attached to the slide rails and coupled to the front and rear frame members through a telescopic relationship.
A suspension mat or web is mounted to the front and rear frame members. The suspension mat supports a foam pad and upholstery cover. The horizontal seating load applied to the frame members is then transferred to the slide rails rather than transferring this load to separate fore and aft seat cushion frame members. As a result, the number of frame components in a seat assembly is reduced with the slide rails serving as a load carrying member for the horizontal seating loads in the seat cushion frame. The cushion frame is thus integrated with the slide tracks to reduce the number of frame components.
The seat back frame can be similarly constructed with lateral frame members formed by extruded components to enable the frame members to be made of varying lengths depending on the seat width. Upright frame members along the lateral sides of the seat back can be configured to telescopingly connect to the extruded frame members and to use common upright members for a variety of seat widths.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.